When you hear the word, “frail,” you probably envision a very old, very thin person huddled under an afghan in a wheelchair. However, frailty is much more common than you’d think. According to Johns Hopkins Medicine, one in 25 Americans between the ages of 65 and 74 are frail, with the number rising to one in four over the age of 84.

So exactly what does it mean to be frail?

“Frail” is not just a label, like “decrepit” and “feeble,” which we assign to older people. It’s a medical condition that can put you at much greater risk for infections, falls, disabilities, illnesses that require a hospital stay, and surgical complications. It can also make you up to 20 times less likely to completely rebound from surgery and be forced to move into assisted living or a nursing home.

To determine if you or someone you love is at risk, take a look at the criteria below. At least three of these qualities must apply.

Weight loss: You’ve unintentionally dropped 10 pounds or more in a year.

Weakness: You have trouble standing without assistance or your grip has weakened.

Exhaustion: You’re extremely tired three or more days a week.

Inactivity: You often don’t have the strength or energy to exercise or perform your normal household or social activities.

Slow pace: It takes you six or seven seconds to walk 15 feet.

Don’t panic.

Frailty is not an inevitable part of aging. There are preventive measures you can take to remain strong and keep this condition at bay.

Stay active. While inactivity is a result of frailty, it can also be a cause. As you age, you need to make a concerted effort to keep moving. Shoot for at least 30 minutes of cardiovascular, resistance and/or weight training four or more days per week. When you’re active, you’ll also have a better appetite and be less likely to lose weight and muscle mass. By the same token, cut back on “couch potato” time. In an article in U.S. News & World Report, Dr. Ronan Factora recommends that you limit the time you are sedentary to no more than three hours a day.

Eat healthy. Try to eat three healthy meals per day, with each meal consisting of fruit, vegetables, protein, good fats, whole grains and low-fat dairy products. Don’t scrimp on proteins, which help preserve your muscle mass, boost immune health, support wound healing, help control blood pressure and even help keep your bones strong.

Stay positive and engaged. Johns Hopkins researchers have found that optimism and a positive attitude often promote vitality well into old age. Combine that with plenty of social connections and opportunities to keep your mind active, and you’ll likely stave off frailty and stay fit as a fiddle for years to come.